1. Field of the Invention
The present invention relates to an apparatus for forming pellets from a liquid or flowable medium. More particularly, the present invention relates to such an apparatus in which a medium to be pelletized is delivered to a distribution box and the distribution box comprises means for intermittently expelling portions of the medium to form pellets.
2. Prior Art
There is a need in the art for an apparatus which can reliably, efficiently and consistently produce high quality pellets from a medium. In particular, a need exists in the cleaning products industry for an apparatus which is capable of mixing two or more components to create a mixture, raising the temperature of the mixture to partially or completely liquefy the mixture, and forming pellets from the mixture in a reliable high-volume application.
A brief summary of some previos pellet forming devices follows.
Perky, U.S. Pat. No. 1,022,501, discloses a machine for processing grain into filaments. The grain is preferably cooked before being processed by the machine of Perky. The cooked grain is pressurized by a hand press and the pressure forces the grain out of holes in the sides of a hollow cylinder.
Meakin, U.S. Pat. No. 2,391,638, discloses an apparatus for making pellets, which is particularly directed to pelletizing material such as sodium, magnesium or gun powder which is dangerous to handle in the presence of oxygen. In the apparatus of Meakin, an extrusion chamber is defined by a cylindrical die having a plurality of holes formed therein. A shaft coupled to the cylindrical die rotates the die. A feed screw feeds material to be pelletized into the interior of the die and an extrusion roller is located in a fixed position within the die below the feed screw inlet. The material to be pelletized is fed by gravity between the inside surface of the die and the extrusion roller, and rotation of the die crushes the material through the holes in the die to form pellets which fall to a collection area below the die.
Fisher, U.S. Pat. No. 2,764,951, discloses a pellet mill employing a perforated annular die and a plurality of rolls mounted within the die for forcing the material to be pelletized through the perforations in the die. The die of Fisher is mounted on a horizontal axis for rotation thereof, and the rollers are mounted on a stationary support within the die. Knives are mounted adjacent the outer surface of the die to cut off the extruded material in pellets of the desired length. An improved version of the Fisher apparatus is disclosed in Curran et al., U.S. Pat. No. 2,887,718.
Cann, U.S. Pat. No. 3,786,645, discloses an apparatus for making compacted pellets of solid phase carbon dioxide. The apparatus of Cann includes an annular die having a plurality of radial extrusion passages therein and a CO.sub.2 injector for flashing liquid carbon dioxide to form snow within the die immediately ahead of a compression zone formed by an eccentric impeller mounted for movement around the die. The impeller compacts and extrudes the snow outwardly through the extrusion passages, forming rod-like extrusions of solid phase carbon dioxide. The rod-like extrusions break off under their own weight after leaving the extrusion passages or, may be broken off by a deflector to form pellets of a desired maximum length.
While various type of apparatus for forming pellets are disclosed in the prior art, a need still exists for a pellet forming apparatus which can form pellets from a mixture which includes a liquid component, the apparatus including a means for intermittently expelling the mixture from the interior of the apparatus in discrete portions, the apparatus also capable of operating reliably in a high-volume production capacity.